Heat sink

ABSTRACT

A heat sink comprises a fin of the heat sink and a cooling set located on the fin of the heat sink. The fin of the heat sink includes a heat conduction portion and a plurality of cooling sheets extended integrally from the heat conduction portion. The heat conduction portion is hollow to form a housing space with at least one opening. The cooling set includes a butting member and a bracing member that are held in the housing space through the opening. The bracing member supports the butting member in the housing space to butt the heat conduction portion. The housing space also holds a cooling liquid and is sealed by a lid on the opening. The integrated cooling sheets and heat conduction portion can improve cooling efficiency and rapidly conduct a greater amount of heat to perform cooling.

FIELD OF THE INVENTION

The present invention relates to a heat sink and particularly to a heat sink installed on a heat source of an electronic device to disperse heat therefrom.

BACKGROUND OF THE INVENTION

Processing and operation speeds of devices in computer systems such as CPU and graphic cards increase constantly. Operation temperatures of electronic devices also are higher. How to effectively and quickly lower the operation temperatures of the electronic devices to maintain regular operation has become a focused issue in the industry.

R.O.C. patent Nos. 1316384, M363615, 1312654 and 1309149 disclose various types of heat sinks. They commonly have fins of a heat sink and a heat conduction duct coupling thereto. The heat conduction duct is in contact with a heat source of an electronic device to transfer heat generated by the heat source to the fins of the heat sink to be dispersed. The heat conduction duct is drawn to form a negative pressure inside and filled with cooling liquid which has a lower boiling point and is easily evaporated. The heat conduction duct has a section in contact with the heat source and heated. The cooling liquid in the heat conduction duct quickly evaporates. The vapor of the cooling liquid flows to another end of the heat conduction duct under a small pressure difference and releases heat and is condensed to become liquid again. The liquid flows back along the wall of the heat conduction duct through a capillary structure. Such a circulation performs repeatedly to continuously carry away the heat of the heat source to lower the temperature.

While the aforesaid conventional techniques can quickly transfer heat to the fins of the heat sink to disperse the heat according to characteristics of the heat conduction duct, they still have problems in practice, notably:

1. The capillary structure located on the inner wall of the heat conduction duct generally is formed by sintering, sand blasting or embedded internally. Fabrication is complex, and fabrication time and cost are higher.

2. The heat conduction duct and fins of the heat sink generally are bonded by soldering or insertion coupling. A medium is contained between materials, such as a solder required in the soldering, and air becomes the medium in the insertion coupling. As a result, heat resistance value increases between the heat conduction duct and the fins of the heat sink due to the medium, and heat conduction efficiency is lower or instantaneous heat absorption capability suffers.

SUMMARY OF THE INVENTION

The primary object of the present invention is to solve the aforesaid disadvantage so that heat on the heat conduction duct can be directly conducted to the fins without going through the medium and also to reduce fabrication complexity of the capillary structure on the inner wall of the heat conduction duct.

To achieve the foregoing object, the present invention provides a heat sink which includes a fin of the heat sink and a cooling set located in the fin of the heat sink. The fin of the heat sink has a heat conduction portion and a plurality of cooling sheets integrally extended from the heat conduction portion. The heat conduction portion is hollow to form a housing space which has at least one end formed an opening. The cooling set has a butting member and a bracing member that are held in the housing space through the opening. The bracing member supports the butting member in the housing space in contact with the heat conduction portion. The housing space holds a cooling liquid and is sealed by a lid on the opening. The cooling liquid generates phase alteration and capillary function in the housing space to allow the heat conduction portion to conduct heat. Moreover, because the cooling sheets and heat conduction portion are formed integrally, the cooling sheets can directly disperse heat conducted from the heat conduction portion.

Compared with the conventional techniques, the present invention provides many benefits, notably:

1. The butting member is in contact with and anchored on the heat conduction portion through the bracing member without additional process such as sintering or other means, hence production cost can be saved.

2. As the cooling sheets and the heat conduction portion are formed integrally, there is no medium interposed between them, hence heat on the heat conduction portion can be directly conducted to the cooling sheets to improve cooling efficiency.

The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is an exploded view of the first embodiment of the present invention.

FIG. 3 is a sectional view of the first embodiment of the present invention.

FIG. 4 is a sectional view of a second embodiment of the present invention.

FIG. 5 is a sectional view of a third embodiment of the present invention.

FIG. 6 is a sectional view of a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 and 2, the present invention provides a heat sink which includes a fin 10 of the heat sink and a cooling set 20 located in the fin 10 of the heat sink. The fin 10 of the heat sink includes a heat conduction portion 12 and a plurality of cooling sheets 11 located on the heat conduction portion 12. In an embodiment shown in the drawings, the cooling sheets 11 are extended radially from the heat conduction portion 12 and formed integrally therewith, such as through an aluminum extrusion process. Hence there is no need of additional fabrication process such as soldering or other means to bond the cooling sheets 11 to the heat conduction portion 12. The heat conduction portion 12 is hollow to form a housing space 13. The housing space 13 has at least one end formed an opening 14. The cooling set 20 includes a butting member 21 and a bracing member 22 that are held in the housing space 13 through the opening 14. The bracing member 22 supports the butting member 21 in the housing space 13 to butt the inner wall of the heat conduction portion 12 to form a capillary structure, thus formed the main structure of the present invention.

In an embodiment of the present invention, the butting member 21 is a mesh article, such as a copper mesh. The bracing member 22 is a spring supporting the mesh article. The heat conduction portion 12 has a recess 15 on the periphery of the opening 14 and a lid 16 to seal the opening 14 to confine the butting member 21 and bracing member 22 in the housing space 13. The lid 16 has one end surface on the same plane of the end surface of the heat conduction portion 12. The lid 16 also has an aperture 17 communicating to the housing space 13. Referring to FIG. 3, the housing space 13, in addition to holding the butting member 21 and bracing member 22, also holds a cooling liquid 18. During fabrication process, an air drawing device (not shown in the drawings) may be deployed to suck air from the housing space 13 through the aperture 17 of the lid 16 to form a vacuum condition in the housing space 13. Then the aperture 17 is sealed. The lid 16 is a heat conductor with high heat conductivity, and can be directly or indirectly in contact with a heat source 31 of an electronic device 30 to quickly absorb the heat therefrom through the characteristics of the heat conductor. Thereby the cooling liquid 18 close to the lid 16 (namely the cooling liquid 18 at one end of the heat conduction portion 12) is heated and vaporized. The heat of the heat source 31 is conducted through the vapor of the cooling liquid 18 to another end of the heat conduction portion 12 and condensed to become the cooling liquid 18 in the liquid state again. Thus the heat of the heat source 31 can be conducted to the entire heat conduction portion 12 and further directly conducted to the radial cooling sheets 11 to be dispersed. Due to the heat conduction portion 12 and cooling sheets 11 are formed integrally, there is no medium interposed between them, hence the heat can be conducted rapidly. The condensed cooling liquid 18 flows back to the end where the lid 16 is located through the capillary structure formed on the butting member 21. As a result, heat conduction can be performed through such a repetitive phase alteration to disperse heat from the heat source 31 of the electronic device 30.

The number of the heat conduction portion 12 is not limited to only one as discussed in the aforesaid embodiment. The cooling sheets 11 also are not restricted to the radial form. Referring to FIG. 4, multiple numbers of the heat conduction portions 12 may be included. The cooling sheets 11 may be spaced and parallel with each other on the heat conduction portion 12 during fabrication, and formed in an integrated manner with the heat conduction portion 12. The end surface of the lid 16 may be at the different planes from the end surface of the heat conduction portion 12, such as jutting outside the fin 10 of the heat sink shown in the drawing. Moreover, the heat conduction portion 12 is not limited to the center of the cooling sheets 11 as depicted in the previous embodiment. FIGS. 5 and 6 illustrate other embodiments with the heat conduction portion 12 located at one end of the cooling sheets 11. In FIG. 5, the heat conduction portion 12 has an upper side and a lower side in parallel with each other. In FIG. 6, the upper and lower sides of the heat conduction portion 12 are not parallel. The vapor of the cooling liquid 18 reaches the upper side of the heat conduction portion 12 and condenses. Through an angle formed by the non-parallel upper and lower sides, the condensed cooling liquid can quickly flow back the lower side of the heat conduction portion 12.

As a conclusion, the heat sink provided by the present invention mainly includes the heat conduction portion 12 located on the fin 10 of the heat sink, and a plurality of cooling sheets 11 integrally extended from the heat conduction portion 12. The heat conduction portion 12 is hollow to form the housing space 13 to hold the cooling liquid 18, and the housing space 13 also holds the butting member 21 and bracing member 22. The bracing member 22 supports the butting member 21 in the housing space 13 to butt the heat conduction portion 12 to form a capillary structure. Compared with the conventional technique, the present invention provides many advantages, notably:

1. The butting member 21 in the heat conduction portion 12 is supported by the bracing member 22 in contact with the heat conduction portion 12 and anchored thereon, no sintering or other means is needed for anchoring. Hence production time and cost can be reduced.

2. As the cooling sheets 11 and heat conduction portion 12 are integrally formed, there is no medium interposed between them, hence heat of the heat conduction portion 12 can be directly conducted to the cooling sheets 11 to improve cooling efficiency.

While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention. 

1. A heat sink, comprising: a fin including a heat conduction portion extended integrally to form a plurality of cooling sheets, the heat conduction portion being hollow to form a housing space which includes at least one end formed an opening thereon; and a cooling set which includes a butting member and a bracing member that are held in the housing space through the opening, the bracing member supporting the butting member in the housing space in contact with the heat conduction portion, the housing space also holding a cooling liquid and being sealed by a lid on the opening.
 2. The heat sink of claim 1, wherein the cooling sheets and the heat conduction portion are integrally formed through aluminum extrusion.
 3. The heat sink of claim 1, wherein the cooling sheets are integrally extended from the heat conduction portion in a radial manner.
 4. The heat sink of claim 1, wherein the cooling sheets are integrally extended from the heat conduction portion in parallel with each other.
 5. The heat sink of claim 1, wherein the lid includes an end surface which is on a same plane with an end surface of the heat conduction portion.
 6. The heat sink of claim 1, wherein the lid includes an end surface which is on different planes with an end surface of the heat conduction portion.
 7. The heat sink of claim 1, wherein the butting member is a mesh article.
 8. The heat sink of claim 1, wherein the heat conduction portion includes a recess on the periphery of the opening to hold the lid.
 9. The heat sink of claim 1, wherein the lid includes an aperture communicating to the housing space.
 10. The heat sink of claim 1, wherein the lid is a heat conductor with high heat conductivity.
 11. The heat sink of claim 1, wherein the bracing member is a spring. 